I have run into a strange problem with mis-fires.

Background

Rem 700 in 7mm-08 failry new ( it has a J lock)

Factory Winchester and Remington Ammo fires fine.

Problem is with my handloads

CCI BR2 primers - never touched by hand - same lot used with other re-loads - even same box - other loads no problem
Using VArget and XMR 4064 powder - works fine in other guns. worked up to 42 grains of each with a 140 Nosler AB.
Using new WW brass - has been neck sized in a Lee Collect die, primer flash hole reamed - nothing else. No lub used in the resizing.

I am getting random mis fires - about 1 in 5. Also having erratic groups. One is great .75", the next is 3".

Firing pin is hitting primer, but only a samll dent.
On the ones that fire, the primers look much different than the factory ones. I can 't explain it well. Looks like the pin indent is pushed out a little. Primner is rounded on the edges. This is not a hot load. I may try to post a picture.

What's going on?

It's not the gun - factory ammo shoots fine.
It's not me oversizing and having too much headspace - I only neck sized the brass
I am seating the primers by hand with a hand primer and putting sold pressure on the primer.
Yes, I pulled all the loads and they had powder in them.

I am starting to think the brass is oversized from the factory and I have too much head space, and then the firing pin is just pushing the case forward.

Any one ever seen this? Any other Idea's.

Thanks

quote:

Originally posted by trigger:


"I am starting to think the brass is oversized from the factory and I have too much head space, and then the firing pin is just pushing the case forward.

Any one ever seen this? "
Thanks

Head space is a strong canidate.The shoulder may be pushed back a little too far. Deep primer pockets another but probably not. I've seen a few batches of mil ammo( .308 & 8X57 lately where the primer is inserted too deep.) Either primer or pocket ,one.Short firing pin????? sounds like a little thought will deliver you the culprit. roger

Update -

I pulled the bullets and dumped the powder on the 4 mis-fires I had Saturday. Tried firing the primers only in the same gun. 3 of the 4 fired. I tried the 1 remaing mis-fire 4 times.
Still no fire. Then tried in another gun - a browning A-bolt. It fired.

I noticed that the J lock was moving on the Remington bolt. Thought it might be dragging on the firing pin. Got to playing with it and I managed to lock the bolt and I don't have a key.

It's my nephew's rifle. I have a key in the mail now.

I am going to post in the Gunsmith Forum to see if anyone has seen problem with a J lock causing problems.

trigger, I'll bet a dollar to a donut you're bumping the shoulder back just a bit to much. If you just back your die out 1/8 of a turn your problem will go away. Jim

Can you eyeball a new piece of brass against a once fired one and compare shoulders?

Also, try seating the bullets out long so they hit the rifling and give you headspace that way. Also load exactly like you are doing except use some once fired brass, see if the problem goes away. All of that should give you some answers, if not maybe change primers!

Just re-read your post, erratic grouping also has me thinking headspace. Do any of the primers protrude, are they out further than what you remember seating them?

Trigger,

I agree 100% with bartshe, Mark & Jim White; you're describing a classic case of "heaspace", eg., misfires and light primer hits. I would do the following:

Fire some factory ammo in the rifle, get a candle, soot the case necks and set the Neck Sizing Die so you can see excatly if you are pushing the should back.

Yes, there could be other reasons, the die, the shell holder, etc, but the root cause is still the same "headspace".

Cheers,

Gerry

In a 7mm/08 the pressure is high enough that primers won't protrude with excessive headspace. They may have a "rivet" look that would be different from factory rounda.
A quick and dirty method to check for headspace would be to add "scotch" tabe to the cartridge base until you can just feeh the shoulder touch. Mike the tape and you have head space.
Good luck1

Be sure you are using the correct shell-holder when you resize. If necessary, mike it to see that the depth from rim to base is correct. If this dimension is too small, you are sizing the cases more than you think.

Gentlemen,

Remember all he is doing here is neck sizing with a collet die, so I do not believe that he is setting the shoulder back any.

Is it possible to set the shoulder back with a collet die? I haven't used one yet (have one for 22 hornet but am still working on a big lot of unfired brass). At my rate it will be august before I need to fiddle with it.

Mark hit the nail on the head! The rest of you just didn't see that he was using the lee collet die to neck size. I just happen to have one in 7-08. I have used it a lot without any of the problems stated here. I can't do any experimenting as the 7-08 is my son's rifle, he has it down in NC at ft. Bragg. However, looking at the die and seeing how it works, I don't see how it could set the shoulder back, in fact that's one of the claims that's made for it. You can neck size without touching the shoulder.

That said, I have to agree that it sounds like that's what happening. My next move would be to call Lee, the question to ask would be "have you ever heard of a collet die setting back a shoulder"?

I just got an idea. I smoked the neck/shoulder area of a fired 7-08 case. I removed the collet from the body of the die, and using a #2 shell holder, slid the case into the collet. The soot was distrubed up to about .030 from the shoulder! I then slid the case in finger tight without the shell holder to simulate a shell holder of less thickness. It went all the way to the junction of the neck and shoulder, however the collet did NOT contact the main taper of the shoulder. It looks like the inside of the collet is a longer angle than the neck.

It will be interesting to see how this plays out, what the final answer will be!.

"[QUOTE]Originally posted by Mark:
Gentlemen,

Remember all he is doing here is neck sizing with a collet die, so I do not believe that he is setting the shoulder back any."

That is probably a given. The new cases being used Might be made with the shoulder being driven back just at or beyond the tolerance limit. The chamber may be to the high side or????? any how HEAD SPACE is still a strong canadate. Try some of that tape on a BRAND NEW case that you just reloaded.

Had a problem a few years back that was similar with a mod. 340, in 30-30. The primers were seated a little deep I took the bolt apart , however, and cleaned all the gunk, dried grease and varnish that had accumulated in it over a 47 year period. Even with deep primers it fired after that but the combination of primer depth, worn firing pin and crud caused the problem.I guess it is possible that head space played a small role here also. roger

Trigger,

I was having the same problem w/ a Savage 110 in 30-06. Small dents in WLR primers. I switched to Fed primers and the misfires went away. Did you disassemble the bolt and make sure everything was clean? I like to run a pipe cleaner through and oil it alittle.

Let us know what happens.

Good Luck!

Reloader

Thanks for the suggestions. I am using the Lee collect die with the supplied shell holder. And the die works fine with the A-bolt and RP brass. If I told you how well the A-Bolt shoots, you would call me a liar.

More data. Some I just remembered.


When I first started working with this rifle I made some handloads using RP brass fired in the A-Bolt and neck sized with the same Lee collect die, got fair groups.

I then put on a Timney trigger, same brass, same results.

Wanting to keep the brass seperate between the two rifles, I ordered WW brass when I ordered the glass bedding kit.

Glass bedded the rifle. Started at 40 grains and worked up to 42 gains with the new brass.
That's when the misfires and erratc groups started.

Thought maybe some binding between the trigger group and the bedded stock. Did not find anything, but cleaned up the excess bedding anyway.
Bought some factory WW from Walmart and tried again last weekend.

Factory shoots great-- under 1 inch. Handloads still mis-fire 1 or 4 or 5.

Last night I checked the headspace on the gun with gauges.
It's fine.


Thinking of ordering some new brass. Going to throughly clean the bolt when I get it unlocked.

Also may try my preferred method of fire forming improved cases -- neck up the brass with my 308 die and then partial resize with the full length 7-08 die until the
bolt will just close. If this mis-fires, My guess is. I either have a gun problem (light strike, short pin) or deep primer pockets.

This was suppose to be quick and easy project.

OK

I think I found a way to neasure the difference in head space between the cases.
I found my 308Win Forrester headspace case length gauge (a chambered steel tube w/ precision cuts on the ends)

Put my go gauge in it and got a measurement from case head to end of tube. Did the same for the No-go and Field. Difference in measurements mathced differences in measurements marked on the gauges.

I then measure my remaining unfired WW cases the same way. Most were at or .001 over the go guage reading.
6 at .001 under and 4 at .002 under. So I have 10 or 44 cases shorter than the Go Gauge.

I also checked some fired cases almost .004 over the go gauge
Unfired WW and RP factory loaded ammo - .001 over go gauge

As soon as I get the damn J lock key, I will try to fire the 10 short primed cases in the gun.

Keep n mind I am measuring with cheap calipers, my Starrets are off for repair.

So take .004 from the gun headspace and add in .001 to .002 from the case, then the tollerances of the firing pin and the primer seating depth (about.001) and I could see it mis-firing.